“Curb, Channel and Coordinate: The Constitutionalisation of International Courts and Tribunals”. in The Contribution of International and Supranational Courts to the Rule of Law . G. D. Baere &J. Wouters. Cheltenham, Elgar Publishing, 2015: 355-369. From the vantage point of normative political philosophy the preceding chapters in this volume offer several lessons and further research questions of how to assess and promote the legitimacy of these ICs. Several proposals amount to measures of constitutionalisation of ICs. Section I identifies some of the hitherto understudied arenas where the authors remind us that the perceived legitimacy of the ICs matters if they are to secure their various objectives. Section II addresses one central standard of legitimacy: the content of the concept of the Rule of Law, which remains contested both as an objective of ICs, and as a requirement on their operation. I stipulate that two central underlying values justify several if not all rule of law norms: non-domination and stable legitimate expectations. Respect for human rights is a further substantive value which many but not all contributors include in the concept. I then consider two main challenges to the legitimacy of ICs from rule of law standards. One is the possible fragmentation and the legal uncertainty that may ensue. Section III thus summarizes the chapters’ insights about the alleged fragmentation wrought by so many ICs. Section IV considers some further challenges to the objectives and performance of ICs by these rule of law standards. Their multiple objectives require that the judges and arbitrators enjoy a wide berth of discretion in interpretation and adjudication. The following two sections responds to these fears. Section V elaborates how the power of ICs is constrained by their complex interrelationship with domestic authorities and Subsidiarity. Section VI considers several ways to regulate the discretion of the ICs to reduce the risks of fragmentation and domination. [SSRN][WEB].